This randomized Phase III trial will compare sequential chemotherapy with doxorubicin, paclitaxel, and cyclophosphamide to combined doxorubicin and cyclophosphamide followed by paclitaxel for disease-free and overall survival. The effect of increasing the dose intensity of adjuvant chemotherapy (decreasing the interval between chemotherapy courses from 21 to 14 days) on the disease-free interval and overall survival will be determined. The toxicities of these regimens will be determined.